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Heat of Annealing in Simple Alkali Silicate Glasses
Author(s) -
TISCHER R. E.
Publication year - 1969
Publication title -
journal of the american ceramic society
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.9
H-Index - 196
eISSN - 1551-2916
pISSN - 0002-7820
DOI - 10.1111/j.1151-2916.1969.tb09202.x
Subject(s) - annealing (glass) , metastability , enthalpy , alkali metal , thermodynamics , crystallization , silicate , materials science , sodium silicate , glass transition , silicate glass , mineralogy , chemistry , composite material , polymer , physics , organic chemistry
The enthalpy changes associated with annealing of glass were studied in simple and mixed alkali silicate glasses. The data indicate that during prolonged annealing the glass comes to a metastable equilibrium state and has a unique heat of solution which depends on its fictive temperature. The heats of solution of these glasses show a linear dependence on fictive temperature, and the magnitude of this dependence is related to the molar volume of the glass. The significance of these heat effects is discussed. The maximum heat effects which can occur on annealing sodium silicate glasses were measured and were approximately half as large as the enthalpy changes associated with the structural arrangements that occur during crystallization of these glasses.